Ultrasound guided shockwave lithotripsy, commonly known as ESWL or extracorporeal shockwave lithotripsy, refers to a system for treating stones or calculi, normally by disintegration for ultimate removal or discharge from the body.
It is particularly desirable to properly focus the shock waves on the stone to avoid damage to healthy tissue about the stone. However, ureteral stones are very difficult, if not impossible, to visualize with ultrasound, and thus accurate focusing of the equipment has been a problem.
One known procedure, in lithotripsy systems, for location of calculi to be disintegrated involves the use of x-ray means and is referred to in U.S. Pat. No. 4,741,008, issued to Kurt Franke on Apr. 26, 1988. This x-ray means normally comprises rather elaborate equipment particularly adpated for use as an adjunct of the lithotripsy equipment to provide a visual representation of a calculi.